Since the Events have a time stamp, are the duplicates showing exact same time for submission?
Did you submit the listing from within the Auctiva one-page lister or from the button "Post Now" and target listing box checked on the Saved Listings page? If it's the later, are you sure only one was checked?
This is beginning to sound like a Support Case problem and you should enter one with Auctiva. Use the HELP link at top of page and filing Support Case is on lower right of the new page.
Danno